This invention relates to tension rollers which are rotatably mounted on machine parts for the purpose of enabling the adjustment of the tightness of a driving belt.
A tension roller of this type is disclosed in DE-GM No. 7203614, comprising a rolling bearing pressed onto the seating surface of a solid support. In order to ensure a sufficiently tight fastening, a relatively tight press fit must be provided whenever other fastening elements are not utilized. The support has an eccentric bore about which the tension roller is able to rotate and which at the same time is used to mount the tension roller to another machine part. As a result of the provision of this bore, the support has a variable radial elasticity about its circumference. The resilience is thus greater in the vicinity of the bore than it is in the remaining solid portion. For this reason, the inner ring of the bearing is deformed and, depending on the degree of press fit, deviates more or less from its ideal circular shape. This alone, during mounting of the bearing, causes severe conditions which often lead to the premature failure of the tension roller. Up until now this disadvantage could only be mitigated by maintaining the greatest possible distance between the eccentric bore and the seating surface, thereby providing sufficient material to increase the radial rigidity in the vicinity of the eccentric bore. For this reason, an optimization of the tightening capacity by means of the greatest possible eccentricity of the bore was not possible.